Anti-friction device for ski boots and skis



Dec. 1, 1970 WERNER ETAL 3,544,123

ANTI-FRICTION DEVICE FOR SKI BOOTS AND SKIS Filed March 29.- 1968ZSheetS-She et 1 INVENTORS III/WK 11 751mm rm at 252mm:

Q1/6662, PE T514901! 1010410)! I WISTMJU Dec. 1, 1970 WERNER EI'AL3,544,123

ANTI-FRICTION DEVICE FOR SKI BOOTS AND SKIS Filed March 29. 1968 2'Sheets-SheetB INVENTORS [RANK D. mum Y 131111. .5. PHZRSEII Mam,psmzswv, Jomvsamms-mu United States Patent 3,544,123 ANTI-FRICTIONDEVICE FOR SKI BOOTS AND SKIS Frank D. Werner, Bloomington, and Paul S.Petersen, Minnetonka, Minn., assignors, by mesne assignments, to SportsTechnology, Inc., Eden Prairie, Minn, a corporation of Delaware FiledMar. 29, 1968, Ser. No. 717,214 Int. Cl. A63c 9/00 US. Cl. 28011.35 13Claims ABSTRACT OF THE DISCLOSURE An anti-friction unit to be mounted onthe top of a ski and positioned underneath a ski boot so that when theski boot is held in lateral release bindings, the antifriction devicewill permit the boot to move laterally within acceptable forcevariations regardless of the load distribution on the boot, and made tobe substantially unaffected by dirt, rust, ice or other foreignmaterials.

BACKGROUND OF THE INVENTION Field of the invention The present inventionrelates to friction control devices for reducing the effective frictionbetween two surfaces, in particular for controlling the friction betweenthe top of a ski and the sole of a boot held in bindings on the ski.

The prior art It has long been a problem with so-called safety bindingsin skis to have a binding which will hold the boot snuggly when normalskiing is encountered and yet will positively and reliably laterallyrelease the boot at the same time high downward loads on the boot areencountered.

U. S. Pat. No. 3,079,163 shows a safety binding including a movableplate on the top of the ski which is used in an attempt to reducefriction. This device is not adaptable to general use with otherbindings. Further, the mounting and construtcion of the device makes itsusceptible to foreign material or ice. The unit does not embodyfeatures that minimize friction in all situations, nor does it providefor automatic re-set.

The use of plates of so-called low friction materials fixed to the skiis not particularly helpful because the reduction in friction is notsufficient. For example, an average load setting for lateral release toebindings is about fifty pounds lateral force. When a skier is leaning rforward, it is possible to have a three or four hundred pound downwardload on the ball of the foot. Even socalled low friction materials havea static coefiicient of friction of .14 to 0.4. The increased lateralforce necessary to slide the boot resulting from the friction of theboot sole on a fixed plate makes variations in the lateral release loadsoutside of tolerable limits necessary for safe binding operation. Thepresence of sand, mud, rust or ice will cause drastic changes in releaseload. Release force is different for wet boot soles or dry boot soles.

SUMMARY OF THE INVENTION The present invention relates to ananti-friction device which reduces the coefficient of friction betweentwo devices which are subjected to changing loads and which must releaselaterally with respect to each other within acceptable variations from apreset load regardless of the forces applied between the two members.The primary usage is for positive releasing of a ski boot from lateralrelease ski bindings. The unit is not adversely affected by load on theboot or foreign materials.

It is an object of the present invention to present a Patented Dec. 1,197) "ice BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevationalview of the boot shown in place in a typical safety release binding;

FIG. 2 is a top plan view taken as on line 2-2 in FIG. 1;

FIG. 3 is an exploded view of the device made accord ing to the presentinvention to show the interior details detail.

FIG. 4 is a fragmentary enlarged side elevational view of the forwardportion of the anti-friction device made according to the presentinvention with parts in section and parts broken away;

FIG. 5 is a fragmentary bottom plan View of the device of the presentinvention showing the unit when it is in its released position in afirst direction;

FIG. 6 is a fragmentary bottom view showing the device in its releasedpositionof FIG. 5, with the bottom plate removed to show the positioningof the center member; and

FIG. 7 is a fragmentary bottom view of the device taken with the bottomplate of the unit removed to show the position of the internal memberscarrier in its normal centered position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the figures, a skiboot 10 is fastened to a lateral release toe piece 11 and a life releaseheel binding 12, both mounted onto a ski 13 and holding the ski bootfirmly in place on the ski. The binding toe piece 11 is made so that itcan be adjusted in the amount of lateral release force which isnecessary for it to release the boot, and it will pivot with respect toits mounting plate to release laterally as shown in dotted lines in FIG.2. The amount of force necessary for the lateral release varies and canbe set with an adjusting screw 14 in the usual manner. Many differenttoe pieces of this general configuration are available commercially andare in wide use. The heel on each binding 12 generally is a verticalrelease so that when the heel is lifted under sufficient force as in aforward fall, the heel will release, and when the leg is twisted,theoretically the toe piece is released. This Will free the skiers legfrom the ski. The heel binding is also a commercially available unit ofusual or preferred design.

What many times happens in skiing is that the friction between the soleof the boot, the bottom surface of which is shown at 15 and the topsurface 16 of the ski, will increase to a point where the forcetransmitted by the leg will be so great that the leg bones will break.This is largely due to varying loads on the boot sole from forwardleaning but also can be from rust, gravel, ice or other foreign materialbetween the boot and the ski. In order to make the amount of frictionbetween the sole of the boot and the top of the ski uniformand controlthe amount of lateral transverse force necessary to release the toebinding 11 to its dotted position within acceptable limits, ananti-friction or friction control device generally designated 20 isplaced between the toe portion of the boot and the top of the ski.

In the exploded view, FIG. 3, it can be seen that the friction controldevice comprises a base plate 21 which The base plate comprises a flatplate-like member of hardened steel, preferably stainless steel, whichis triangular shaped as shown. The plate is hard enough to preventroller indentation. The leading edge area of the base plate 21 includesa guide lip 23 which is integral with the base portion, and is otfsettherefrom through the use of a transition section 24 which extendsupwardly from the base plate itself to the guide lip. The guide lipextends forwardly slightly from the main part of the base plate andthere is an opening 25 provided through the transition section. Thisopening is centrally located on the transition section and is made sothat it will permit a hairpin type spring 27 to pass therethrough, asshown in FIG. 3. The hairpin spring 27 has a closed end 28, and a pairof legs 29, 29 which extend through the opening 25. The legs 29, 29 areflattened at their outer ends, as shown, and have upwardly extendingprongs or ears 32, 32. The ears, as perhaps best seen in FIG. 4, extendupwardly from the legs themselves and when the spring is in place, theears extend upwardly above the top of the lip 23.

A roller cage and bearing member 33 is provided to be positioned on topof the base plate 21. The roller cage 33 comprises a member having flatplate-like sections 34 adjacent the outer sides thereof and a centerraised section 35. The center raised section forms a pocket (shown inFIG. 7) into which the hairpin spring 27 is fitted. The pocket hasopenings 36 along the edges thereof in the area where the closed end orrounded end of the hairpin spring rides. The closed end of the hairpinspring can be retained in place with a suitable small fastening lug 37if desired. This will retain the hairpin spring from exaggeratedsideways movement during actuation.

The bearing case 33 also is used to form a plurality of roller pockets.There are two forward pockets 40, 40 which are formed so that the axesof rollers 41 therein will intersect the centerline of a pivot ormounting hole 42 at the rear portions of the bearing cage. A thirdbearing pocket 43 is formed in the raised member 35 just to the rear ofthe spring pocket and a roller 41 also fits inside this pocket 43. Theaxis of the roller in pocket 43 also intersects the pivot point at thepivot opening 42.

The bearing cage is made of a low friction material which has highstrength, such as nylon, and the rollers .41 are of size so that theywill protrude just above and below the edges of the surfaces definingthe pockets 40 and 43. The rollers 41 ride against the top surface ofthe base plate 21 and the bottom surface of a cover plate 45 rides ontop of the rollers.

The cover plate 45 has a top member which is provided with twostifiening indentations 46, 46 and has turned down flanges 47 along thelongitudinal edges of the plate. The flanges 47 are of size so that whenthe unit is assembled as shown in FIG. 4 the flange closely clears thetop of the base plate 21. At the forward edge of the cover plate 45 thecover plate has a turned over guide member 48 which forms a U-shape incross section as shown in FIG. 4 and is made to fit below and retain thelip 23. The guide member 48 does not extend all the way out to theperipheral edges of plate 45, for ease of manufacture, but does gosubstantially to each of the sides of the cover plate. The lip 23 fitsinside the U-shape of the guide member and extends above the lower edgesof flanges 47 as shown.

Referring specifically to FIGS. 5, 6' and 7, it can be seen that theguide member 48 is provided with an opening 51 on the bottom sidethereof. This opening is positioned to align with the upright ears 32,32 of the spring, and is of size so that the spring ears fit inside theopening when it is under slight compression. The opening 51 is forwardlyof the outer edge of the lip 23 and the ears also clear the outer edgeof this lip.

Thus, in assembly, the spring legs 29, 29 extend through the opening 25in the transition section 24 of the lip 23 so that the prongs extendinto the opening 51. The unit is retained in assembled position with arivet 52 that is shouldered. The rivet is fastened to hold the bottomplate, the roller cage, and the top cover 45 together for relativemovement about a single pivotal axis adjacent the rear of the unit. Thebearing cage opening 42 has a cone shaped surface 53, and the coverplate also has a pivot opening 54 having an interior cone shaped surface55. When the rivet 52 is in place, holding the unit together, the flangeportion 52A of the rivet bears against the conical portion 55surrounding the opening 54. The rivet holds the bottom surface of thecover plate in contact with a boss 59 on the roller cage surroundingopening '42 so that there is a bearing surface for relative movementbetween the two parts, namely the bearing cage and the cover plate. Thebearing cage is of low friction material so the pivot moves easily. Thebearing cage also bears on the bottom plate 21 to carry load at the rearportions of the unit from the cover to the bottom plate.

It screws are used to mount the unit, there is a shoulder on theinterior of the rivet 52 which carries the load from the screw. Thescrew does not bear against the flange portion 52A. Thus, the screw atthe rear of the anti-friction unit can be tightened down securelywithout causing binding between the pivoting plates.

When the unit is used, the base plate is fastened to the ski in asuitable manner such as with adhesive material 22 or with screws asdesired. The rivet will hold the pivoting plates 45, 33 and 21 togetherfor pivoting about its central rear axis. At the forward edge, the guidemember 48 will hold the cover plate and the base plate from separatingbecause the guide member 48 will engage the underside of the lip 23.

The unit is placed substantially under the ball of the foot or slightlyforwardly therefrom so that the three rollers are in position to carrymost of the weight of the foot from the ski boot when the skier leansforwardly. Because the unit has some thickness, a small block can beplaced under the heel portion of the boot to keep the boot level.

When the foot is to be released, the anti-friction device will do itunder rolling friction. The movement of the top plate, which will movewith the boot, relative to the bottom plate which stays with the ski issupported by free rollers.

Assuming that a transverse force is encountered which is suificient topermit the release binding 11 of the toe to release, the force willcause the cover plate 45 to tend to pivot about the axis of opening 54on rivet 52. The cover plate will bear against the rollers 41, and therollers 41 will thus roll against the top of the bottom plate 21 and becarried by the cage 33 in this rolling motion. The rolling motionresults in a maximum reduction of friction because the rollers are notpinned, but roll freely within the cage. Also, the axis of the rollerscoincide back at the axis of pivot of the cover so that there is verylittle tendency for the rollers to slide rather than roll. When thecover plate pivots, one end of the opening 51, depending on thedirection of pivoting of the cover plate, will engage one of the ears 32of the spring 27 and will move that car to compress the hairpin spring27 by tending to move the two legs 29 together. This is shown in FIG. 5,wherein the cover plate (looking at it from the bottom of the unit) haspivoted in direction as indicated by the arrow 60 and has caused the twolegs 29 of the spring 27 to move together. This spring force is notgreat enough to substantially affect the releasing force for thebinding, but is suflicient to return the bearing cage and cover plate tocenter when the boot is released.

As can be seen, one flange 47 will engage an edge portion 61 of thetransition section 24 on the base plate, and this will act as a stop toprevent the cover plate from pivoting too far. Likewise, in the oppositedirection the transition portion 24 and the flange 47 on the oppositeside of the cover plate will act as stops to limit movement of the coverplate in the opposite direction.

When the boot has been released from the ski, the spring 27 will drivethe cover plate back to its normal position. The hairpin spring will actto cause this centering.

When the rollers 41 roll, the bearing cage moves substantially half theangular distance of the cover plate. Thus, at the same time that thecover plate shifts, the bearing cage shifts slightly, and thecompression of the spring takes place largely between one end surface ofthe opening 25 and one end surface of opening 51. There are small lugs62 provided in the edges of the pocket for the spring 27 to hold thespring properly positioned and initially compress it slightly when firstpositioned.

It should be also noted that in order to install the forward screws inthe bottom plate tothe ski, the unit merely has to be moved so that thecover plate is in its full sideways position, and the screw holes at theforward end of the base plate 21 will be uncovered and thus the screwscan be installed. The cover plate movement is sufficient to permit thisinstallation as shown in FIG. 1.

The spring 27 also acts not only to center the cover plate with respectto the base plate, but also to center the roller cage each time. Becausethe basic action on the spring takes place between the edges of theopening 25 and the edges of the opening 51, the rear portions of thespring react against the lugs 62 to center the roller cage each time itsreturned to center. Sometimes, if the rollers slide rather than roll thecage could become misplaced and then the unit would not operate as well.However, this centering action of the spring acts to keep the rollercage centered after each time it has been pivoted as well as recenteringthe cover plate with respect to the base plate. The ears or prongs 32 onthe spring 27 are constrained in opening '51 so they prevent the springfrom slipping out of place. The ears are made long enough to insurethis.

The turned down flanges 47 act as stitfeners for the cover plate, aswell, and also acts as a scraper for ice and foreign material to makesure that when the cover plate pivots it will scrape away any ice thatmight have built up along the edges of the base plate or on the ski, andkeep this foreign material out of the way of the rollers. It can be seenthat the clearance between the edges 47 and the base plate 21 is quitesmall and this will insure that no foreign material gets into the rollercage to adversely affect operation.

What is claimed is:

1. A friction control unit positioned between an upper surface of a skiand a lower surface of the sole of a ski boot, wherein lateral releasebinding means for releasably securing the boot to the ski are provided,comprising an assembly of a first plate, a center bearing cage member,and a second cover plate pivotally mounted together about a common axisadjacent the rear of the assembly, means to mount said first plate tothe top surface of said ski with said common axis substantiallyperpendicular to the upper surface of said ski and substantiallycentered transversely on the ski, the forward portions of said assemblylying under a ski boot fastened in the binding means adjacent the frontof the boot and roller means, said bearing cage member having pocketsdefined therethrough, said roller means being positioned within saidpockets in said center bearing cage member for transferring force fromsaid cover plate to said first plate in the forward portions of saidassembly.

2. The friction control unit of claim 1 wherein said second cover plateand said first plate having interlocking guide and lip means at theforward portions thereof, said guide and lip means preventing verticalseparation of said cover plateand said first plate in the forwardportions of said assembly but permitting movement of the cover platerelative the ski about the common axis.

3. The combination as specified in claim 2 wherein said rolling meanscomprise substantially cylindricalrollers having rolling axesintersecting the common axis of said assembly.

4. The combination as specified in claim 3 wherein said center bearingcage for retaining said rollers includes low friction means fortransferring force from said second plate to said first plate in thearea adjacent to the pivot between said second plate and said firstplate.

5. The combination as specified in claim 2 wherein said second coverplate has two longitudinal edges and has flange means extending alongboth of the longitudinal edges thereof, said flange means being ofdimension to very closely clear the upper surface of said first platewhen said second cover plate pivots relative to said first plate.

6. A friction reducing unit for mounting between a first surfacecomprising the upper surface of a ski and a second surface, said skihaving a longitudinal direction, comprising a first plate member adaptedto be attached to said first surface, a second plate membersubstantially parallel to said first plate member, means pivotallymounting said first and second plate members together about a pivot axisat substantially right angles to said longitudinal direction so thatportions of said second plate member will move transversely relative tosaid first plate member, said second plate member being adapted tosupport said second surface, rolling members positioned between saidfirst and said second plate members and effec tive to transfer forcefrom said second plate member to said first plate member and to rollwhen said second plate member moves relative to said first plate member,said rolling members being positioned spaced from said pivotal axis insaid longitudinal direction, and bearing cage means for retaining saidrolling members in a predetermined orientation for rolling motionbetween said first and said second plate members, said bearing cagemeans being positioned between said first and second plate members andhaving low friction means thereon for transferring force from saidsecond plate member to said first plate member adjacent to the pivotaxis between said second plate member and said first plate member.

7. A friction reducing unit for mounting between a first surfacecomprising the upper surface of a ski and a second surface, said skihaving a longitudinal direction, comprising a first plate member adaptedto be attached to said first surface, a second plate membersubstantially parallel to said first plate member, means pivotallymounting said first and second plate members together about a pivot axisat substantially right angles to said longitudinal direction so thatportions of said second plate member will move transversely relative tosaid first plate member, said second plate member being adapted tosupport said second surface, rolling members positioned between saidfirst and said second plate members and effective to transfer force fromsaid second plate member to said first plate member and to roll whensaid second plate member moves relative to said first plate member, saidrolling members being positioned spaced from said pivotal axis in saidlongitudinal direction, and said second plate member comprising a covermember having a flange extending along the longitudinal edges thereof,said flange being of dimension to very closely clear the upper surfaceof said first plate member when said second plate member pivots relativeto said first plate member.

8. A device for controlling friction load between a ski boot and the topof a ski, said ski boot being retained on said ski with lateral releasebindings, comprising an assembly of two spaced apart substantiallyparallel plates, means pivotally mounting said plates with respect toeach other for limited pivotal movement about a pivotal axis adjacentone end thereof, a plurality of rolling members between said plates, andsupporting said plates directly, means for constraining said rollingmembers for rolling contact with both of said plates in a predeterminedpath as said plates pivot with respect to each other, and means to mountsaid assembly in position on said ski with said plates and the rollingmembers substantially under the ball of a foot of a skier wearing saidski boot, and with the pivot axis positioned rearwardly of the ball ofsaid 7 foot.

9. The combination as specified in claim 8, wherein said rolling memberscomprise substantially cylindrical rollers having axes extendinggenerally in longitudinal direction of the ski.

10. The combination as specified in claim 8 and guide means adjacent theends of said plates opposite from said pivotal axis, said guide meansforming complemental interlocking means between said plates to preventseparation of said plates from predetermined planes.

11. The combination as specified in claim 8 and means cooperatingbetween said plates forming stop members which limit relative pivotalmovement between said plates.

12. The combination as specified in claim 8 and spring means biasing anupper one of said plates toward a normal position substantiallyoverlying a lower one of said plates.

13. The combination as specified in claim 8 wherein said means forconstraining said rolling members for rolling contact with both of saidplates comprises a separate bearing cage member, said bearing cagemember being pivotally mounted between said plates about said pivotalaxis.

References Cited UNITED STATES PATENTS 2,676,813 4/1954 Beyl28011.35(CB) 2,745,672 5/1956 Meier 28011.35(CB) 2,846,232 8/1958Sch-nell 280--11.35(HA) 3,079,163 2/1963 De Beausacq 280-1l.35(AA)FOREIGN PATENTS 1,358,624 3/ 1964 France.

431,349 8/ 1967 Switzerland.

BANJAMI-N HERSH, Primary Examiner M. L. SMITH, Assistant Examiner 11g?UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION' a Patent No.3,544,123 Dated December 1, 1970 Inventor(s) Frank D. Werner and Paul S.Petersen It is certified that: error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 54, "0.4" should be -'-.o4--. Column 2, line 1:

delete "detail." and insert --thereof;. Column 5, line 58,

after "boot" insert Edward n mew, I WILLIAM x. 50mm, on. ArrestingOfficer flioner or Pat-eats

